Apparatus for demonstrating or testing the transmission of light by ophthalmic glass and the like



Aug. 14, T929. 9,999,999

C. S. PYSER APPARATUS FOR DEMONSTRATING 0R TESTING THE TRANSMISSION oF LIGHT BY OPHTHALMIG GLASS AND THE LIKE Filed Nov. 2l, 1922 2 Sheets-Sheet 1 NVENTOR ATTORNEY Aug. 14, 1923. 31,464,999

C. S. PYSER APPARATUS FOR DEMONSTRATING OR TESTING THE TRANSMISSION OF' LIGHT BY OPHTHALMIC GLASS AND THE LIKE Filed Nov. 2l 1922 2 Sheets-Sheet 2 Chaer umt Pgoer INVENTOR Patented Aug. 14, i923 5 intatte nr centeno CHARLES STUART JPYSER, 0F LONDON, ENGLAND, ASSIGNOlR/.T THE HAYLAER OPTICAL COMPANY, LIMITED, 01E LONDON, ENGLAND, A. CORPORATION.

APPARATUS JE'OR. DEMONSTRATING OR TESTING THE TRANSMISSJON OF LllGlEIT BY OPHTHIC GLASS AND THE LIKE.

Application tiled November 21, 1922. Serial Ito. 602,417.

To all whom t may concern:

Be it known that l, CHARLES STUART Prsnn, a subject of the King of England, residing at 38 Blandford Street London, W. 1, in the Kingdom of England, have 1nvented certain new and useful Improvements in Apparatus for Demonstrating or Testing the Transmission of Li ht by O hthalmic Glass and the like, of which the fo lowing is a specification.

This invention refers to improvements in or relating to apparatus for demonstrating or testing the transmission of light by ophthalmic glass and the like, and it has for its object to provide a convenient and portable apparatus by means of which an optician or other person can readily demonstrate to his clients in a practical and convincing manner the merits of certain specially prepared glass as a medium for excluding or absorbing the noxious ultra-violet rays, and also its transparency to light.

The inventlon has more particular reference to testing apparatus of the kind comprising a lamp chamber enclosin an arc .lamp having carbons producing a light rich in ultra-violet rays, an opening in said chamber, a filter or screen of glass or the like in saidopening permitting only the passage of ultra-violet rays through the said screen on to the articles to be tested.-

Now according to the present invention we provide apparatus of the kind described adapted for demonstrating or testing the transmission 'of light by ophthalmic glass and the like, by the provision of a fiuorescent screen to co-operate with the screen or li ht iilter and to test the light-transmitting qualities of materials placed between sai screens. l

In order that the present invention may be clearly understood and more readily carried into eilect it is hereinafter described with l reference to the accompanying drawings, in

which Figure 1 is a sectional side elevation of a simple form of apparatus constructed in accor ance with the present invention;

Figure 2 is a front view of said apparatus;

Figure 3 is a plan view corresponding to .Figure 1, and

igure 4 is an enlarged perspective view of the slide and the opaque screen.

According to the present invention the improved apparatus comprises a suitable tiren proof casing a of metal and insulating material conveniently of substantially flat rectangular formation. ln the particular con.- struction shown the casing is formed from a single sheet of metal which is bent round at the rea-r end so as to form two spaced parallel side members between which are secured by flanges thereon the top and bottom sheets or strips of insulating material to which the resistance elements of the lamp are connected. The rear portion of the casing is suitably perforated or fenestrated to allow of the escape of the heat. The one end or front portion of the said apparatus is conveniently constructed to form a lamp-house a containing a suitable illuminating device for instance as a miniature electric arc lamp The rear portion of the case a of the apparatus is adapted to contain a suitable resistance or resistances c with external terminals d providing means whereby the appa ratus can be adapted for voltages varying within suitable limits, such for instance as voltages varying from 100 to 250. The lamp b employed 1s preferably one adapted toproduce a light rich in ultra-violet rays and in ,the case of an electric arc lamp being employed, this can be effected by the employment of chromic-steel pencils in the place of the usual carbons. These chromic-steel encils besides producing a light rich in u traviolet rays possess the advantage that they will burn for long periods without appreciable consumption. The arc-striking mecha` nism may conveniently though not necessarily, be of the kind described in the specification of British Letters Patent No. 160,569, in which the arc is struck by means of a spring-controlled ring clutch d working in conjunction with an adjustable stop e and in which means such as the insulated n r knob f are provided for manuall feeding the electrodes as they are consume At the front a of the instrument and in front of the arc b and in a suitably constructed slide g movable in guides g is placed a piece ot opaque glass or other material k which will exclude or absorb all visible light and permit only the ultra-violet rays to pass out..

ln front of this opa ue screen it and arranged in another sli e or holder il is pretiti Milt

lill@ vided another screen y' formed of uranium glass upon which the ultra-violetirays after passingfthrough thed firstopa'que screen v71, are adapted "touoresce The'holderc' in which. this screen jlis mounted may 'conveniently be connected to a pair ofl lngil tudinally"slidable supports or`bzfrs'lcfand guidesrlllso that the distanceffthefsaid screen j from the opaquecreemh canQbe v varied at will. The connection between the screen or holder j adlthesaid bars 7c fis preferably of Ya pivotal nature, -somthat the;

said 'uranium screenl j; can 'be turnddown: .out of position" when requled. i i; .In operation when thelight is turned fon the ultra-violet rays willbe seen to loresce on the uranium screen j and lthen bythe-in-l sertion of the glass or glasses to betested E between .the two screens'hand j thel merit or relative merits ofv theglass or glassesso` placed can be clearly seen and demonstrated?.

even to persons quite unskilled in optical work. In. cases where a piece of Crookes:4

,i fglass is placed between two screens, the glass,

although quite transparent to ordinary light, will be seen to act on the fluorescent screen like an eclipse, shutting oil' moreor less completely the eli'ect thereon of the Y' The comparative values .l i ultra-Violet rays. of. 'other' forms of tinted and smoked glass canalso-be- 'nestedv and demonstrated, as will be readily understood.

By the'attachment of a suitable holding device (not shown) the ultra-violet rays can be utilized 'for projection `on to precious stones and V-pearls to test their genuine merits.

---\ being spaced fromeach other whereby the 'vf'.whichone or both oflth'e screensarefadj'iistably mounted in relation tothe source of 3.'Apparatus-of thecharacter describedv comprising a casingcontaining a so'ur'ce'o 'f' light rich in ultra-violetrays,-ascreenl of'Y opaque glass adapted-'to absorb visible' light to permit ultra-violet rays to-p ass,land a"l 2. Apparatus Maccording to claim 1, in

l iuorescent screen of uranium glass `placed cooperating with the ultra-violetl rays,V l whereby the light transmitting qualities of betested. e 1- f4. In anA apparatus of-'the lcharacter de?- scribed, the combination 'ora casing con- -1 taining a sourcefof light, an opaque 'screen arranged in front of the light,i a'nd'a second screen made vof "-uranium glass upon which rays of light after passing throughy the iirs't jscreen are adapted to fluoresc,saidscreens I light transmitting qualitiesfof,-V materials in front of and spaced from the first screen' placed between the two screens can betested.

'In testimony`-whereof I have' hereunto ,f signed my name. l l'- CHARLES STUART PYSER.

materials placed-'between theV two screens can Q 0 

